comparison dsp/mfcc/MFCC.c @ 250:a106e551e9a4

...

+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+#include "mfcc.h"
+#include "SBFFT.h"
+#include "windows.h"
+
+/*
+ * 
+ *  Initialise the MFCC structure and return a pointer to a 
+ *  feature vector 
+ * 
+ */
+
+extern mfcc_t* init_mfcc(int fftSize, int nceps , int samplingRate, int WANT_C0){
+
+  int i,j;
+  /* Calculate at startup */
+  double *freqs, *lower, *center, *upper, *triangleHeight, *fftFreqs;
+  
+  /* Allocate space for the structure */
+  mfcc_t* mfcc_p = (mfcc_t*)malloc(sizeof(mfcc_t));
+  
+  mfcc_p->lowestFrequency   = 66.6666666;
+  mfcc_p->linearFilters     = 13;
+  mfcc_p->linearSpacing     = 66.66666666;
+  mfcc_p->logFilters        = 27;
+  mfcc_p->logSpacing        = 1.0711703;
+  
+  /* FFT and analysis window sizes */
+  mfcc_p->fftSize           = fftSize;
+
+  mfcc_p->totalFilters      = mfcc_p->linearFilters + mfcc_p->logFilters;
+  
+  mfcc_p->samplingRate      = samplingRate;
+  
+  /* The number of cepstral componenents */
+  mfcc_p->nceps             = nceps;
+
+  /* Set if user want C0 */
+  mfcc_p->WANT_C0           = WANT_C0;
+  
+  /* Allocate space for feature vector */
+  if (mfcc_p->WANT_C0==1) {
+    mfcc_p->ceps              = (double*)calloc(nceps+1,sizeof(double));
+  } else {
+    mfcc_p->ceps              = (double*)calloc(nceps,sizeof(double));
+  }
+ 
+  /* Allocate space for local vectors */
+  mfcc_p->mfccDCTMatrix     = (double**)calloc(mfcc_p->nceps+1, sizeof(double*));
+  for (i=0;i<mfcc_p->nceps+1; i++) {
+    mfcc_p->mfccDCTMatrix[i]= (double*)calloc(mfcc_p->totalFilters, sizeof(double)); 
+  }
+
+  mfcc_p->mfccFilterWeights = (double**)calloc(mfcc_p->totalFilters, sizeof(double*));
+  for (i=0;i<mfcc_p->totalFilters; i++) {
+    mfcc_p->mfccFilterWeights[i] = (double*)calloc(mfcc_p->fftSize, sizeof(double)); 
+  }
+
+  freqs  = (double*)calloc(mfcc_p->totalFilters+2,sizeof(double));
+  
+  lower  = (double*)calloc(mfcc_p->totalFilters,sizeof(double));
+  center = (double*)calloc(mfcc_p->totalFilters,sizeof(double));
+  upper  = (double*)calloc(mfcc_p->totalFilters,sizeof(double));
+
+  triangleHeight = (double*)calloc(mfcc_p->totalFilters,sizeof(double));
+  fftFreqs       = (double*)calloc(mfcc_p->fftSize,sizeof(double));
+  
+  for (i=0;i<mfcc_p->linearFilters;i++) {
+    freqs[i] = mfcc_p->lowestFrequency + ((double)i) * mfcc_p->linearSpacing;
+  }
+  
+  for (i=mfcc_p->linearFilters; i<mfcc_p->totalFilters+2; i++) {
+    freqs[i] = freqs[mfcc_p->linearFilters-1] * 
+               pow(mfcc_p->logSpacing, (double)(i-mfcc_p->linearFilters+1));
+  }
+  
+  /* Define lower, center and upper */
+  memcpy(lower,  freqs,mfcc_p->totalFilters*sizeof(double));
+  memcpy(center, &freqs[1],mfcc_p->totalFilters*sizeof(double));
+  memcpy(upper,  &freqs[2],mfcc_p->totalFilters*sizeof(double));
+    
+  for (i=0;i<mfcc_p->totalFilters;i++){
+      triangleHeight[i] = 2./(upper[i]-lower[i]);
+  }
+  
+  for (i=0;i<mfcc_p->fftSize;i++){
+      fftFreqs[i] = ((double) i / ((double) mfcc_p->fftSize ) * 
+                     (double) mfcc_p->samplingRate);
+  }
+
+  /* Build now the mccFilterWeight matrix */
+  for (i=0;i<mfcc_p->totalFilters;i++){
+
+    for (j=0;j<mfcc_p->fftSize;j++) {
+      
+        if ((fftFreqs[j] > lower[i]) && (fftFreqs[j] <= center[i])) {
+          
+          mfcc_p->mfccFilterWeights[i][j] = triangleHeight[i] * 
+                                            (fftFreqs[j]-lower[i]) / (center[i]-lower[i]); 
+          
+        }
+        else
+        {
+          
+          mfcc_p->mfccFilterWeights[i][j] = 0.0;
+        
+        }
+
+        if ((fftFreqs[j]>center[i]) && (fftFreqs[j]<upper[i])) {
+
+          mfcc_p->mfccFilterWeights[i][j] = mfcc_p->mfccFilterWeights[i][j] + triangleHeight[i] * (upper[i]-fftFreqs[j]) 
+                                            / (upper[i]-center[i]);
+        }
+        else
+        {
+
+          mfcc_p->mfccFilterWeights[i][j] = mfcc_p->mfccFilterWeights[i][j] + 0.0;
+            
+        }
+    }
+
+  }
+
+#ifndef PI    
+#define PI 3.14159265358979323846264338327950288
+#endif 
+
+  /*
+   * 
+   * We calculate now mfccDCT matrix 
+   * NB: +1 because of the DC component
+   * 
+   */
+  
+  for (i=0; i<nceps+1; i++) {
+    for (j=0; j<mfcc_p->totalFilters; j++) {
+        mfcc_p->mfccDCTMatrix[i][j] = (1./sqrt((double) mfcc_p->totalFilters / 2.))  
+                                      * cos((double) i * ((double) j + 0.5) / (double) mfcc_p->totalFilters * PI);
+    }
+  }
+
+  for (j=0;j<mfcc_p->totalFilters;j++){
+    mfcc_p->mfccDCTMatrix[0][j]     =  (sqrt(2.)/2.) * mfcc_p->mfccDCTMatrix[0][j];
+  }
+   
+  /* The analysis window */
+  mfcc_p->window = hamming(mfcc_p->fftSize);
+
+  /* Allocate memory for the FFT */
+  mfcc_p->imagIn      = (double*)calloc(mfcc_p->fftSize,sizeof(double));
+  mfcc_p->realOut     = (double*)calloc(mfcc_p->fftSize,sizeof(double));
+  mfcc_p->imagOut     = (double*)calloc(mfcc_p->fftSize,sizeof(double));
+  
+  free(freqs);
+  free(lower);
+  free(center);
+  free(upper);
+  free(triangleHeight);
+  free(fftFreqs);
+
+  return mfcc_p;
+
+}
+
+/*
+ *
+ *  Free the memory that has been allocated 
+ *
+ */ 
+
+extern void close_mfcc(mfcc_t* mfcc_p) {
+
+  int i;
+  
+  /* Free the structure */
+  for (i=0;i<mfcc_p->nceps+1;i++) {
+    free(mfcc_p->mfccDCTMatrix[i]);
+  }
+  free(mfcc_p->mfccDCTMatrix);
+
+  for (i=0;i<mfcc_p->totalFilters; i++) {
+    free(mfcc_p->mfccFilterWeights[i]);
+  }
+  free(mfcc_p->mfccFilterWeights);
+
+  /* Free the feature vector */
+  free(mfcc_p->ceps);
+
+  /* The analysis window */
+  free(mfcc_p->window);
+
+  /* Free the FFT */
+  free(mfcc_p->imagIn);
+  free(mfcc_p->realOut);
+  free(mfcc_p->imagOut);
+
+  /* Free the structure itself */
+  free(mfcc_p);
+  mfcc_p = NULL;
+
+}
+
+/*
+ * 
+ * Extract the MFCC on the input frame 
+ * 
+ */ 
+
+
+// looks like we have to have length = mfcc_p->fftSize ??????
+
+extern int do_mfcc(mfcc_t* mfcc_p, double* frame, int length){
+
+  int i,j;
+  
+  double *fftMag;
+  double *earMag;
+
+  double *inputData;
+  
+  double tmp;
+
+  earMag    = (double*)calloc(mfcc_p->totalFilters, sizeof(double));
+  inputData = (double*)calloc(mfcc_p->fftSize, sizeof(double)); 
+  
+  /* Zero-pad if needed */
+  memcpy(inputData, frame, length*sizeof(double));
+  
+  /* Calculate the fft on the input frame */
+  fft_process(mfcc_p->fftSize, 0, inputData, mfcc_p->imagIn, mfcc_p->realOut, mfcc_p->imagOut);
+
+  /* Get the magnitude */
+  fftMag = abs_fft(mfcc_p->realOut, mfcc_p->imagOut, mfcc_p->fftSize);
+
+  /* Multiply by mfccFilterWeights */
+  for (i=0;i<mfcc_p->totalFilters;i++) {
+    tmp = 0.;
+    for(j=0;j<mfcc_p->fftSize/2; j++) {
+      tmp = tmp + (mfcc_p->mfccFilterWeights[i][j]*fftMag[j]);
+    }
+    if (tmp>0)
+		earMag[i] = log10(tmp);
+	else
+		earMag[i] = 0.0;
+  }
+
+  /*
+   * 
+   * Calculate now the ceptral coefficients 
+   * with or without the DC component
+   *
+   */
+  
+   if (mfcc_p->WANT_C0==1) {
+     
+    for (i=0;i<mfcc_p->nceps+1;i++) {
+      tmp = 0.;
+      for (j=0;j<mfcc_p->totalFilters;j++){
+        tmp = tmp + mfcc_p->mfccDCTMatrix[i][j]*earMag[j];
+      }
+      /* Send to workspace */
+      mfcc_p->ceps[i] = tmp;
+    }
+
+   }
+    else 
+   {  
+      for (i=1;i<mfcc_p->nceps+1;i++) {
+        tmp = 0.;
+        for (j=0;j<mfcc_p->totalFilters;j++){
+          tmp = tmp + mfcc_p->mfccDCTMatrix[i][j]*earMag[j];
+        }
+        /* Send to workspace */
+        mfcc_p->ceps[i-1] = tmp;
+      }
+  }
+    
+  free(fftMag);
+  free(earMag);
+  free(inputData);
+
+  return mfcc_p->nceps;
+
+}
+
+
+
+